Newly discovered aspects of catalysis of amino acid dehydrogenation by glutamate dehydrogenase-aminotransferase complexes will be studied. This study will include;, (a) the role of other amino acids as activators of reactions catalyzed by these complexes; (b) the properties of these complexes; and (c) the structure of covalently cross-linked complexes. Both the physical structure and physiological significance of these complexes will be investigated. Efforts will be made to identify the keto group on aminotransferases. Furthermore, the physiological function of this group as well as the nature and function of the DPNH binding site on the aminotransferase will be explored. The possibility that other physiologically significant enzyme-enzyme complexes are formed will be explored.